|Year|Player|Country|Score|To par|Margin of victory|Course|Location|Purse ($)|Winner's share ($)|
|---|---|---|---|---|---|---|---|---|---|
|2014||||||Cherry Hills Country Club|Cherry Hills Village, Colorado|8,000,000|1,440,000|
|2013|Zach Johnson|United States|64-70-69-65=268|–16|2 strokes|Conway Farms Golf Club|Lake Forest, Illinois|8,000,000|1,440,000|
|2012|Rory McIlroy|Northern Ireland|64-68-69-67=268|–20|2 strokes|Crooked Stick Golf Club|Carmel, Indiana|8,000,000|1,440,000|
|2011|Justin Rose|England|63-68-69-71=271|–13|2 strokes|Cog Hill Golf & Country Club|Lemont, Illinois|8,000,000|1,440,000|
|2010|Dustin Johnson|United States|68-70-68-69=275|–9|1 stroke|Cog Hill Golf & Country Club|Lemont, Illinois|7,500,000|1,350,000|
|2009|Tiger Woods (2)|United States|68-67-62-68=265|–19|8 strokes|Cog Hill Golf & Country Club|Lemont, Illinois|7,500,000|1,350,000|
|2008|Camilo Villegas|Colombia|65-66-66-68=265|–15|2 strokes|Bellerive Country Club|Town and Country, Missouri|7,000,000|1,260,000|
|2007|Tiger Woods|United States|67-67-65-63=262|–22|2 strokes|Cog Hill Golf & Country Club|Lemont, Illinois|7,000,000|1,260,000|

Question: how many strokes marked the margin of victory for justin rose in 2011?
Answer: 2